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This paper proposes an original approach to cluster multi-component data sets, including an estimation of the number of clusters. From the construction of a minimal spanning tree with Prim's algorithm, and the assumption that the vertices are approximately distributed according to a Poisson distribution, the number of clusters is estimated by thresholding(More)
This paper deals with noised astronomical multiband image fusion and restoration. The wavelet domain is well adapted for such tasks. In fact, intensity fluctuations corresponding to the noise are most important at the finest resolution and related details coefficients decrease quickly as the scale increases. Real structures in the image will therefore lead(More)
We present new results of our wide-field redshift survey of galaxies in a 182 square degree region of the Shapley Supercluster (SSC) based on observations with the FLAIR-II spectrograph on the UK Schmidt Telescope (UKST). In this paper we present new measurements to give a total sample of redshifts for 710 bright (R ≤ 16.6) galaxies, of which 464 are(More)
Virtual Observatories give us access to huge amounts of image data that are often redundant. Our goal is to take advantage of this redundancy by combining images of the same field of view into a single object. To achieve this goal, we propose to develop a multi-source data fusion method that relies on probability and band-limited signal theory. The target(More)
We introduce a new multiscale restoration algorithm for images with few photons counts and its use for denoising XMM data. We use a thresholding of the wavelet space so as to remove the noise contribution at each scale while preserving the multiscale information of the signal. Contrary to other algorithms the signal restoration process is the same whatever(More)
Compact elliptical galaxies are characterized by small sizes and high stellar densities. They are thought to form through tidal stripping of massive progenitors. However, only a handful of them were known, preventing us from understanding the role played by this mechanism in galaxy evolution. We present a population of 21 compact elliptical galaxies(More)
Structure and dynamics of the Shapley Supercluster ⋆ Velocity catalogue, general morphology and mass. Abstract. We present results of our wide-field redshift survey of galaxies in a 285 square degree region of the Shapley Supercluster (SSC), based on a set of 10529 velocity measurements (including 1201 new ones) on 8632 galaxies obtained from various(More)
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